Bearing Lubricants For Pulverizing Equipment

ABSTRACT

The invention relates to a method of lubricating the bearings of solid fuel pulverizers, for example, coal pulverizers. The method involves supplying to the bearings a lubricating composition designed to have superior performance compared to conventional coal pulverizer bearing lubricants. The invention also provides a bearing lubricant for a coal pulverizer as well as its use in coal pulverizing equipment to improve the service life and/or durability of bearings in coal pulverizing equipment. The invention also provides an additive composition for use in a bearing lubricant for a coal pulverizer, as well as the use of the additive composition to improve the service life and/or performance of the bearing lubricant.

FIELD OF THE INVENTION

The invention relates to a method of lubricating the bearings of solidfuel pulverizers, for example, coal pulverizers. The method involvessupplying to the bearings a lubricating composition designed to havesuperior performance compared to conventional coal pulverizer bearinglubricants. The invention also provides a bearing lubricant for a coalpulverizer as well as its use in coal pulverizing equipment to improvethe service life and/or durability of bearings in coal pulverizingequipment. The invention also provides an additive composition for usein a bearing lubricant for a coal pulverizer, as well as the use of theadditive composition to improve the service life and/or performance ofthe bearing lubricant.

BACKGROUND OF THE INVENTION

Pulverizers are well known for the reduction of the particle size ofsolid fuel to allow for combustion of the solid fuel in a furnace. Apulverizer employs some combination of impact, attrition and crushing toreduce a solid fuel to a particular particle size. Several types ofpulverizer mills can be employed for the pulverization of the solidfuel, for example, coal, to a particulate size appropriate for firing ina furnace. These can include ball-tube mills, impact mills, attritionmills, ball race mills, and ring roll or bowl mills. Most typically,however, bowl mills with integral classification equipment are employedfor the pulverization of the solid fuel to allow for transport, dryingand direct firing of the pulverized fuel entrained in an air stream.There is an on-going need to improve the mill loading and roll life ofthe bearings of these pulverizers.

Another factor which deteriorates roll life of the bearings in additionto increased mill loading includes solid fuel dust, such as coal dust,for example, which flows into and contaminates the bearings as well asthe lubricant. Typically, pulverizers have an interface between therotatable assembly and stationary shaft that is exposed to atmosphericconditions and a differential pressure across the assembly allows thecoal dust, for example, to flow into the assembly housing the bearings.The ingress of coal at this interface, which allows the shaft to extendthere through and rotate with respect to the journal assembly,contaminates the lubricant and journal bearings thus deteriorating theroll life of the journal bearings.

Some approaches involve complicated mechanical seals and expensive newequipment designed to reduce the amount of dust ingress. However, thesesolution do nothing for the current equipment already in use.

Therefore, there remains a need for a method, and a lubricant, and anadditive package that increases bearing roll life in these pulverisers,which facilitates increased mill loading and prevents damage fromcontamination of the bearings, thus allowing more effective use ofexisting equipment without the need for costly refits and modifications.

SUMMARY OF THE INVENTION

The invention provides a method of lubricating the bearings of a solidfuel pulverizer. The method involved supplying to the bearings alubricating composition designed to have superior performance comparedto conventional solid fuel pulverizer bearing lubricants. Thelubricating composition is designed to have improved dust loadingcapability, in other words, the lubricant is designed to perform betterand/or last longer than conventional lubricants in the harsh conditionsseen in pulverizers, including conditions related to large amounts ofdust in the environment, which does get worked into the lubricant. Theinvention also provides a bearing lubricant for a pulverizer as well asits use in pulverizing equipment to improve the service life and/ordurability of bearings in pulverizing equipment. The invention alsoprovides an additive composition for use in a bearing lubricant for apulverizer, as well as the use of the additive composition to improvethe service life and/or performance of the bearing lubricant. In someembodiments, the solid fuel pulverizer described herein is a coalpulverizer.

The lubricating composition of the invention includes (a) an oil oflubricating viscosity, (b) a phosphorus-containing compound, and (c) anitrogen-containing dispersant, where the phosphorus-containing compoundand the nitrogen-containing dispersant work together to allow for betterperformance in the pulverizer bearing lubricant. In some embodiments,the compositions further include (d) a sulfur-containing compound.

In some embodiments, the invention deals with mineral base oillubricants. In other embodiments, the invention deals with syntheticbase oil lubricants.

The invention provides for various phosphorus-containing compoundincluding an alkyl phosphite, a phosphoric acid ester, an amine salt ofa phosphoric acid ester, or some combination thereof. In someembodiments, the phosphorus-containing compound comprises an alkylphosphite.

The invention provides for various nitrogen-containing dispersantsincluding a polyetheramine, a borated succinimide dispersant, anon-borated succinimide dispersant, a Mannich dispersant comprising thereaction product of (i) a dialkylamine, (ii) an aldehyde and (iii) ahydrocarbyl substituted phenol, as well as any combination of thevarious nitrogen-containing dispersants. In some embodiments, thenitrogen-containing dispersant comprises a non-borated succinimidedispersant. The invention further provides for a lubricant containing analkyl phosphite and a non-borated succinimide dispersant.

In any of these embodiments, the phosphorus-containing compound may bepresent in the lubricant composition from 0.25 or 0.5 up to 2.0 or 1.0percent by weight and the nitrogen-containing dispersant is present inthe lubricant composition from 0.1 or 0.5 up to 2.0 or 1.0 percent byweight, on an oil free basis, which may also be described herein is onan actives basis.

DETAILED DESCRIPTION OF THE INVENTION

Various features and embodiments of the invention will be describedbelow by way of non-limiting illustration.

The Pulverizer and Method of Lubrication

The pulverizers suitable for use with the present invention are notoverly limited. Pulverizers may generally be described as devicesemployable for purposes of effecting the grinding of materials. Morespecifically, the prior art is replete with examples of various types ofapparatus that have been used to effect the grinding of many differentkinds of materials. In this regard, in many instances discernibledifferences of a structural nature can be found to exist betweenindividual pulverizers. The existence of such differences is, in turn,attributable for the most part to the diverse functional requirementsthat are associated with the individual applications in whichpulverizers are designed to be employed. For instance, in the selectionof the particular type of pulverizer that is to be utilized for aspecific application, one of the principal factors to consider is thatof the nature of the material that is to be ground in the apparatus.Coal is one such material wherein there is a need to grind it in orderto render it suitable for use in certain applications. Furthermore,fossil fuel fired power generation systems represent one suchapplication in which it is desired to employ coal, as the source offuel, and wherein a requirement exists to grind, i.e., pulverize, thecoal to render it suitable for use for this purpose, i.e., for use in acoal-fired power generation system. Thus, in some embodiments, thepulverizers used with the invention are coal pulverizers.

In some embodiments, the pulverizers of the invention may include afeeder for feeding solid fuel to the pulverizer, an apparatus forpulverizing the solid fuel, a distribution system for distributing thesolid fuel after the pulverization thereof, a furnace in which the solidfuel is to be burned and the requisite controls for effecting the properoperation of the solid fuel-fired power generation system. Of particularinterest here the apparatus for pulverizing the solid fuel, for example,coal.

In some embodiments, the pulverizer of the present invention is a bowlmill. A bowl mill may essentially consists of a body portion in which agrinding table is mounted for rotation, a plurality of grinding rollersthat coact with the grinding table to effect the grinding of solid fuelinterposed there between, solid fuel supply means for feeding to theinterior of the bowl mill the solid fuel that is to be pulverized, andair supply means for supplying to the interior of the bowl mill the airrequired in the operation of the latter. In accordance with the mode ofoperation of such a bowl mill, the solid fuel, which enters the bowlmill, is pulverized by virtue of the coaction of the grinding rollerswith the grinding table. After being pulverized, the solid fuelparticles are thrown outwardly by centrifugal force whereby theparticles are fed into a stream of air that is entering the bowl mill.The stream of air, which now contains pulverized solid fuel particles,flows through a tortuous path that is established in part by thepositioning within the bowl mill of a suitably supported deflectormeans. As the stream of air and solid fuel particles flows along theaforementioned tortuous path, the sharp turns contained therein effectsthe separation of the coarse solid fuel particles from the air stream.These coarse solid fuel particles are then suitably returned to thegrinding table for further pulverization while the fine solid fuelparticles are carried through the bowl mill in the air stream, and exittherefrom along with the air. Each bowl mill will typically also havebearings, for example, upper bearings and lower bearings associated withthe grinding rollers with the grinding table and/or their mounts.

Each pulverizer will typically also have a lubrication system forsupplying lubricant to its beatings, including the upper and lowerbearings of a bowl mill described, but all the various bearing that maybe found in the various types of pulverizers used in the field.

The present invention provides a lubricant composition for the bearingsof a solid fuel pulverizer and also provides a method of lubricating thebearings of a coal pulverizer by supplying to said bearings thedescribed lubricant composition. The lubricant compositions useful inthe invention are described below.

In some embodiments, the method of the invention involves supplying thedescribed lubricant composition to a coal pulverizer. In someembodiments, the method of the invention involves supplying thedescribed lubricant composition to a bowl mill pulverizer. In someembodiments, the method of the invention involves supplying thedescribed lubricant composition to a bowl mill coal pulverizer. In someembodiments, the method of the invention involves supplying thedescribed lubricant composition to the upper bearings of the pulverizer.In some embodiments, the method of the invention involves supplying thedescribed lubricant composition to the lower bearings of the pulverizer.In some embodiments, the method of the invention involves supplying thedescribed lubricant composition to the upper and lower bearings of thepulverizer, or even all of the bearings in the pulverizer.

The Lubricant Composition

The invention includes a bearing lubricating composition made up of (a)an oil of lubricating viscosity, (b) a phosphorus-containing compound,and (c) a nitrogen-containing dispersant, where thephosphorus-containing compound and the nitrogen-containing dispersantwork together to allow for better performance in the pulverizer bearinglubricant. The invention also provides an additive composition for usein a bearing lubricant for a pulverizer made up of (a) an optionaldiluent which may be an oil of lubricating viscosity or solvent, and (b)a phosphorus-containing compound, and (c) a nitrogen-containingdispersant, where the phosphorus-containing compound and thenitrogen-containing dispersant work together to allow for betterperformance in the pulverizer bearing lubricant. In some embodiments,the compositions further include (d) a sulfur-containing compound.

In some embodiments, the lubricant composition contains from 0.01 to5.0, or from 0.25 to 5.0, or from 0.5 to 5.0, or from 0.5 to 4.0, from0.75 to 3.0, from 0.9 to 2.0, or from 1 to 2, or even 1 or 2 percent byweight of a phosphorus-containing compound, on an actives basis (meaningno diluent oil or solvent is includes, rather the components areconsidered on a neat basis). In some embodiments, the lubricantcomposition contains a phosphorus-containing compound in an amountsufficient to deliver from 0.01 to 5.0, or from 0.025 to 0.5 or from0.025 to 0.25, or from 0.05 to 0.1 percent by weight phosphorus to theoverall lubricant composition.

In some embodiments, the lubricant composition contains from 0.01 or 0.1or 0.25 to 10 or 5 or 4, or from 0.01 or 0.1 or 0.25 to 5, or from 0.1to 1.0, or from 0.4 to 2.0 or 2.5, or from 0.5 to 2.0 percent by weightof a nitrogen-containing dispersant on an actives basis.

In some embodiments, the phosphorus-containing compound and thenitrogen-containing dispersant are present in the lubricant compositionin a ratio from 1:10 to 10:1, or from 1:4 to 4:1, or from 1:2 to 4:1, orfrom 1:1 to 3:1, or even about 2:1, where the ratio is a weight ratioconsidered on an actives free basis. In some embodiments, thephosphorus-containing compound and the nitrogen-containing dispersantare present in the lubricant composition in a ratio from 0.5:1 to 4:1,or from and/or to about 0.5:1, 1:1, 1.2:1, 2:1 or 4:1, where the ratiois a weight ratio considered on an oil free basis.

The Oil of Lubricating Viscosity

One component of the compositions of the invention is an oil oflubricating viscosity, which can be present in a major amount, for alubricant composition, or in a concentrate forming amount, for aconcentrate and/or additive composition.

Suitable oils include natural and synthetic lubricating oils andmixtures thereof. In a fully formulated lubricant, the oil oflubricating viscosity is generally present in a major amount (i.e., anamount greater than 50 percent by weight). Typically, the oil oflubricating viscosity is present in an amount of 75 to 95 percent byweight, and often greater than 80 percent by weight of the overallcomposition.

The base oil component generally makes up 100 parts by weight (pbw) ofthe overall composition with the pbw ranges for the other componentsbeing provided with this 100 pbw of base oil in mind. In otherembodiments, the pbw ranges of the various components, including thebase oils, are provided such that the total of the pbw of all componentsis 100, and thus the pbw values are equivalent to percent by weightvalues. The pbw ranges provided for the various components describedbelow may be taken either way, however, in most embodiments they are tobe read so as to be equivalent to percent by weight values.

The oil of lubricating viscosity may include natural and synthetic oils,oil derived from hydrocracking, hydrogenation, and hydrofinishing,unrefined, refined and refined oils or mixtures thereof. Unrefined oilsare those obtained directly from a natural or synthetic source generallywithout (or with little) further purification treatment. Refined oilsare similar to the unrefined oils except they have been further treatedin one or more purification steps to improve one or more properties.Purification techniques are known in the art and include solventextraction, secondary distillation, acid or base extraction, filtration,percolation and the like. Re-refined oils are also known as reclaimed orreprocessed oils, and are obtained by processes similar to those used toobtain refined oils and often are additionally processed by techniquesdirected to removal of spent additives and oil breakdown products.

Natural oils useful as the oil of lubricating viscosity include animaloils, vegetable oils (e.g., castor oil, lard oil), mineral lubricatingoils such as liquid petroleum oils and solvent-treated or acid-treatedmineral lubricating oils of the paraffinic, naphthenic or mixedparaffinic naphthenic types and oils derived from coal or shale ormixtures thereof.

Synthetic oils of lubricating viscosity include hydrocarbon oils such aspolymerized and interpolymerised olefins (e.g., polybutylenes,polypropylenes, propyleneisobutylene copolymers); poly(1-hexenes),poly(1-octenes), poly(1-decenes), and mixtures thereof; alkyl-benzenes(e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes,di-(2-ethylhexyl)-benzenes); polyphenyls (e.g., biphenyls, terphenyls,alkylated polyphenyls); alkylated biphenyl ethers and alkylated biphenylsulfides and the derivatives, analogs and homologs thereof or mixturesthereof. In some embodiments, the oil of lubricating viscosity used inthe invention is a synthetic oil that includes polymerizedpolyisobutylene, and in some embodiments, the oil of lubricatingviscosity used in the invention is a synthetic oil that includespolymerized polyisobutylene and a polyalphaolefin).

Another synthetic oil of lubricating viscosity include polyol estersother than the hydrocarbyl-capped polyoxyalkylene polyol as disclosedherein, dicarboxylic esters, liquid esters of phosphorus-containingacids (e.g., tricresyl phosphate, trioctyl phosphate, and the diethylester of decane phosphonic acid), or polymeric tetrahydrofurans.Synthetic conventional oil of lubricating viscosity also include thoseproduced by Fischer-Tropsch reactions and typically may behydroisomerised Fischer-Tropsch hydrocarbons or waxes. In oneembodiment, the oil of lubricating viscosity may be prepared by aFischer-Tropsch gas-to-liquid synthetic procedure as well as othergas-to-liquid oils.

Oils of lubricating viscosity may further be defined as specified in theAmerican Petroleum Institute (API) Base Oil InterchangeabilityGuidelines. The five base oil groups are as follows: Group I (sulfurcontent >0.03 percent by weight, and/or <90 percent by weight saturates,viscosity index 80-120); Group II (sulfur content ≦0.03 percent byweight and ≧90 percent by weight saturates, viscosity index 80-120);Group III (sulfur content ≦0.03 percent by weight and ≧90 percent byweight saturates, viscosity index ≧120); Group IV (all polyalphaolefins,or PAO, such as PAO-2, PAO-4, PAO-5, PAO-6, PAO-7 or PAO-8); and GroupV. The oil of lubricating viscosity includes API Group I, Group II,Group III, Group IV, Group V oil or mixtures thereof. In one embodiment,the oil of lubricating viscosity is an API Group I, Group II, Group III,Group IV oil or mixtures thereof. Alternatively, the oil of lubricatingviscosity is often an API Group II, Group III or Group IV oil ormixtures thereof.

In some embodiments, the lubricating oil component of the presentinvention includes a Group II or Group III base oil, or a combinationthereof. These are classifications established by the API (AmericanPetroleum Institute). Group III oils contain <0.03 percent sulfurand >90 percent saturates and have a viscosity index of >120. Group IIoils have a viscosity index of 80 to 120 and contain <0.03 percentsulfur and >90 percent saturates. The oil can also be derived from thehydroisomerization of wax, such as slack wax or a Fischer-Tropschsynthesized wax. Such “Gas-to-Liquid” oils are typically characterizedas Group III.

The compositions of the present invention may include some amount ofGroup I base oils, and even Group IV and Group V base oils.Polyalphaolefins are categorized as Group IV. Group V encompasses “allothers”. However, in some embodiments, the lubricating oil component ofthe invention contains no more than 20, 10, 5, or even 1 percent byweight Group I base oil. These limits may also apply to Group IV orGroup V base oils. In other embodiments, the lubricating oil present inthe compositions of the invention is at least 60, 70, 80, 90, or even 95percent by weight Group II and/or Group III base oil. In someembodiments, the lubricating oil present in the compositions of theinvention is essentially only Group II and/or Group III base oil, wheresmall amounts of other types of base oils may be present but not inamounts that significantly impact the properties or performance of theoverall composition.

In some embodiments, the compositions of the invention include someamount of Group I and/or Group II base oils. In other embodiments, thecompositions of the invention are lubricating compositions where the oilof lubricating viscosity is primarily Group I and/or Group II base oils,or even essentially Group I and/or Group II base oils, or evenexclusively Group I and/or Group II base oils.

In some embodiments, the compositions of the invention include someamount of Group I and/or Group II base oils. In other embodiments, thecompositions of the invention are lubricating compositions where the oilof lubricating viscosity is primarily Group I and/or Group II base oils,or even essentially Group I and/or Group II base oils, or evenexclusively Group I and/or Group II base oils.

The various described oils of lubricating viscosity may be used alone orin combinations. The oil of lubricating viscosity is used in the rangeof about 70 percent by weight to about 99 percent by weight, and inanother embodiment, in the range of about 75 percent by weight to about98 percent by weight, in another embodiment in the range of about 88percent by weight to about 97 percent by weight of the lubricant.

The Phosphorus-Containing Compound

The compositions useful in the invention include a phosphorus-containingcompound.

In some embodiments, the phosphorus-containing compound is a phosphite.Suitable phosphites include those having at least one hydrocarbyl groupwith 4 or more, or 8 or more, or 12 or more, carbon atoms. Typicalranges for the number of carbon atoms on the hydrocarbyl group include 8to 30, or 10 to 24, or 12 to 22, or 14 to 20, or 16 to 18. The phosphitemay be a mono-hydrocarbyl substituted phosphite, a di-hydrocarbylsubstituted phosphite, or a tri-hydrocarbyl substituted phosphite.

In one embodiment, the phosphite is sulphur-free i.e., the phosphite isnot a thiophosphite.

The phosphite having at least one hydrocarbyl group with 4 or morecarbon atoms may be represented by the formulae:

wherein at least one of R³, R⁴ and R⁵ may be a hydrocarbyl groupcontaining at least 4 carbon atoms and the other may be hydrogen or ahydrocarbyl group. In one embodiment, both R³, R⁴ and R⁵ are hydrocarbylgroups. The hydrocarbyl groups may be alkyl, cycloalkyl, aryl, acyclicor mixtures thereof. In the formula with all three groups R³, R⁴ and R⁵,the compound may be a tri-hydrocarbyl substituted phosphite i.e., R³, R⁴and R⁵ are all hydrocarbyl groups.

Alkyl groups may be linear or branched, typically linear, and saturatedor unsaturated, typically saturated. Examples of alkyl groups for R³, R⁴and R⁵ include octyl, 2-ethylhexyl, nonyl, decyl, undecyl, dodecyl,tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl,octadecenyl, nonadecyl, eicosyl or mixtures thereof.

In some embodiments, the phosphorus-containing compound is an amine saltof a phosphate hydrocarbon ester (i.e., an amine salt of a hydrocarbonester of phosphoric acid). The amine salt of a phosphate hydrocarbonester may be derived from an amine salt of a phosphate. The amine saltof the phosphate hydrocarbon ester may be represented by the formula:

Wherein: R³ and R⁴ may be independently hydrogen or hydrocarbontypically containing 4 to 40, or 6 to 30, or 6 to 18, or 8 to 18 carbonatoms, with the proviso that at least one is a hydrocarbon group; andR⁵, R⁶, R⁷ and R⁸ may be independently hydrogen or a hydrocarbyl group,with the proviso that at least one is a hydrocarbyl group. Thehydrocarbon groups of R³ and/or R⁴ may be linear, branched, or cyclic.

Examples of a hydrocarbon group for R³ and/or R⁴ include straight-chainor branched alkyl groups include methyl, ethyl, propyl, butyl, pentyl,hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl,tetradecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl. Additionalexamples include 2-ethylhexl, 4-methyl-2-pentyl, and isopropyl.

Examples of a cyclic hydrocarbon group for R³ and/or R⁴ includecyclopentyl, cyclohexyl, cycloheptyl, methylcyclopentyl,dimethylcyclopentyl, methylcyclopentyl, dimethylcyclopentyl,methylethylcyclopentyl, diethyl-cyclopentyl, methylcyclohexyl,dimethylcyclohexyl, methyl ethylcyclohexyl, diethylcyclohexyl,methylcycloheptyl, dimethylcycloheptyl, methylethyl-cycloheptyl, anddiethylcycloheptyl.

In one embodiment, the phosphate may be an amine salt of a mixture ofmonoalkyl and dialkyl phosphoric acid esters. The monoalkyl and dialkylgroups may be linear or branched.

The amine salt of a phosphate hydrocarbon ester may be derived from anamine such as a primary amine, a secondary amine, a tertiary amine, ormixtures thereof. The amine may be aliphatic, or cyclic, aromatic ornon-aromatic, typically aliphatic. In one embodiment, the amine includesan aliphatic amine such as a tertiary-aliphatic primary amine.

Examples of suitable primary amines include ethylamine, propylamine,butylamine, 2-ethylhexylamine, bis-(2-ethylhexyl)amine, octylamine, anddodecylamine, as well as such fatty amines as n-octylamine,n-decylamine, n-dodecylamine, n-tetradecylamine, n-hexadecylamine,n-octadecylamine and oleylamine. Other useful fatty amines includecommercially available fatty amines such as “Armeen®” amines (productsavailable from Akzo Chemicals, Chicago, Ill.), such as Armeen C, ArmeenO, Armeen OL, Armeen T, Armeen HT, Armeen S and Armeen SD, wherein theletter designation relates to the fatty group, such as coco, oleyl,tallow, or stearyl groups.

Examples of suitable secondary amines include dimethylamine,diethylamine, dipropylamine, dibutylamine, diamylamine, dihexylamine,diheptylamine, methyl ethylamine, ethylbutylamine,N-methyl-1-amino-cyclohexane, Armeen® 2C and ethylamylamine. Thesecondary amines may be cyclic amines such as piperidine, piperazine andmorpholine.

Examples of tertiary amines include tri-n-butylamine, tri-n-octylamine,tri-decylamine, tri-laurylamine, tri-hexadecylamine, anddimethyloleylamine (Armeen® DMOD).

In one embodiment, the amines are in the form of a mixture. Examples ofsuitable mixtures of amines include (i) a tertiary alkyl primary aminewith 11 to 14 carbon atoms, (ii) a tertiary alkyl primary amine with 14to 18 carbon atoms, or (iii) a tertiary alkyl primary amine with 18 to22 carbon atoms. Other examples of tertiary alkyl primary amines includetert-butylamine, tert-hexylamine, tert-octylamine (such as1,1-dimethylhexylamine), tert-decylamine (such as1,1-dimethyloctylamine), tertdodecylamine, tert-tetradecylamine,tert-hexadecylamine, tert-octadecylamine, tert-tetracosanylamine, andtert-octacosanylamine.

In one embodiment, a useful mixture of amines is “Primene® 81R” or“Primene® JMT.” Primene® 81R and Primene® JMT (both produced and sold byRohm & Haas) are mixtures of C11 to C14 tertiary alkyl primary aminesand C18 to C22 tertiary alkyl primary amines respectively.

The amine salt of a phosphate hydrocarbon ester may be prepared as isdescribed in U.S. Pat. No. 6,468,946. Column 10, lines 15 to 63describes phosphoric acid esters formed by reaction of phosphoruscompounds, followed by reaction with an amine to form an amine salt of aphosphate hydrocarbon ester. Column 10, line 64, to column 12, line 23,describes preparative examples of reactions between phosphorus pentoxidewith an alcohol (having 4 to 13 carbon atoms), followed by a reactionwith an amine (typically Primene® 81-R) to form an amine salt of aphosphate hydrocarbon ester.

Suitable phosphorus-containing compounds also include hydrocarbyl aminesalts of dialkyldithiophosphoric acid. Examples of hydrocarbyl aminesalts of dialkyldithiophosphoric acid are represented by the formula:

wherein R²⁶ and R²⁷ are independently branched or linear alkyl groups.R²⁶ and R²⁷ contain about 3 to about 30, preferably about 4 to about 25,more preferably about 5 to about 20, and most preferably about 6 toabout 19 carbon atoms. R²³, R²⁴ and R²⁵ are as described above.

In some embodiments, the hydrocarbyl amine salts ofdialkyldithiophosphoric acid include but are not limited to the reactionproduct(s) of diheptyl or dioctyl or dinonyl dithiophosphoric acids withethylenediamine, morpholine or Primene 81R or mixtures thereof.

The phosphorus-containing compound may be present at 0.01 percent byweight to 5 percent by weight, or 0.1 percent by weight to 3 percent byweight, or 0.2 percent by weight to 1.5 percent by weight, or 0.25percent by weight to 1 percent by weight, or 0.5 percent by weight to 1percent by weight of the described composition.

The Nitrogen-Containing Dispersant

The compositions useful in the invention include a nitrogen-containingdispersant, which in some embodiments is a hydrocarbyl substitutednitrogen containing additive. Suitable hydrocarbyl substituted nitrogencontaining additives for use in the present invention includes additivessometimes referred to as ashless dispersants. Dispersants in general arewell known in the field of lubricants and fuel (though often theseadditives are referred to as fuel detergents when used in fuelapplications). Suitable materials include primarily what is known asashless dispersants and polymeric dispersants. Ashless dispersants areso-called because, as supplied, they do not contain metal and thus donot normally contribute to sulfated ash when added to a lubricant.However, they may, of course, interact with ambient metals once they areadded to a lubricant which includes metal-containing species. Ashlessdispersants are characterized by a polar group attached to a relativelyhigh molecular weight hydrocarbon chain. Examples of such materialsinclude succinimide dispersants, Mannich dispersants, and boratedderivatives thereof.

Mannich dispersants, sometimes referred to as a Mannich base dispersantor Mannich detergents, are the reaction product of ahydrocarbyl-substituted phenol, an aldehyde, and an amine or ammonia.The hydrocarbyl substituent of the hydrocarbyl-substituted phenol canhave 10 to 400, 30 to 180, 10 or 40 to 110 carbon atoms. Thishydrocarbyl substituent can be derived from an olefin or a polyolefin,such as 1-decene, which are commercially available.

The polyolefins, which can form the hydrocarbyl substituent can beprepared, for instance, by polymerizing olefin monomers by well-knownpolymerization methods and are also commercially available. The olefinmonomers include monoolefins, including monoolefins having 2 to 10carbon atoms such as ethylene, propylene, 1-butene, isobutylene, and1-decene. An especially useful monoolefin source is a C4 refinery streamhaving a 35 to 75 weight percent butene content and a 30 to 60 weightpercent isobutene content. Useful olefin monomers also include diolefinssuch as isoprene and 1,3-butadiene. Olefin monomers can also includemixtures of two or more monoolefins, of two or more diolefins, or of oneor more monoolefins and one or more diolefins. Useful polyolefinsinclude polyisobutylenes having a number average molecular weight of 140to 5000, in another instance of 400 to 2500, and in a further instanceof 140 or 500 to 1500. The polyisobutylene can have a vinylidene doublebond content of 5 to 69%, in a second instance of 50 to 69%, and in athird instance of 50 to 95%. The polyolefin can be a homopolymerprepared from a single olefin monomer or a copolymer prepared from amixture of two or more olefin monomers. Also possible as the hydrocarbylsubstituent source are mixtures of two or more homopolymers, two or morecopolymers, or one or more homopolymers and one or more copolymers. Theforegoing description of suitable hydrocarbyl groups or polyolefingroups is also applicable to the hydrocarbyl substituent of thesuccinimide dispersant, described in detail below.

The hydrocarbyl-substituted phenol which is used to prepare the Mannichdispersant can be prepared by alkylating phenol with an olefin orpolyolefin described above, such as a polyisobutylene or polypropylene,using well-known alkylation methods.

The aldehyde used to form the Mannich dispersant can have 1 to 10 carbonatoms, and is generally formaldehyde or a reactive equivalent thereofsuch as formalin or paraformaldehyde.

The amine used to form the Mannich dispersant can be a monoamine or apolyamine, including those materials described below for the succinimidedispersants, including alkanolamines having one or more hydroxyl groups.Useful amines include ethanolamine, diethanolamine, methylamine,dimethylamine, ethylenediamine, dimethylaminopropylamine,diethylenetriamine and 2-(2-amino-ethylamino)ethanol. The Mannichdispersant can be prepared by reacting a hydrocarbyl-substituted phenol,an aldehyde, and an amine as described in U.S. Pat. No. 5,697,988. Inone embodiment, the Mannich reaction product is prepared from analkylphenol derived from a polyisobutylene, formaldehyde, and an aminethat is a primary monoamine, a secondary monoamine, or analkylenediamine, in particular, ethylenediamine or dimethylamine. In oneembodiment, the alkylphenol may be prepared from a high-vinylidenepolyisobutene, having, e.g., greater than 50, greater than 70 or greaterthan 75 percent terminal vinylidene groups (i.e., such percentage ofpolyisobutylene molecules having vinylidene end groups.) The foregoingdescription of the amine is also applicable to the description of theamine used in preparing the succinimide dispersant, described below.

In one embodiment, the Mannich dispersant comprises the reaction productof a hydrocarbyl-substituted phenol, formaldehyde or a reactiveequivalent of formaldehyde, and a primary or secondary amine. In oneembodiment, the Mannich dispersant comprises the reaction product of apolyisobutene-substituted phenol, formaldehyde or a reactive equivalentof formaldehyde, and dimethylamine.

As used herein, the term “hydrocarbyl substituent” or “hydrocarbylgroup” is used in its ordinary sense, which is well-known to thoseskilled in the art. Specifically, it refers to a group having a carbonatom directly attached to the remainder of the molecule and havingpredominantly hydrocarbon character. Examples of hydrocarbyl groupsinclude hydrocarbon substituents, including aliphatic, alicyclic, andaromatic substituents; substituted hydrocarbon substituents, that is,substituents containing non-hydrocarbon groups which, in the context ofthis invention, do not alter the predominantly hydrocarbon nature of thesubstituent; and hetero substituents, that is, substituents whichsimilarly have a predominantly hydrocarbon character but contain otherthan carbon in a ring or chain. A more detailed definition of the term“hydrocarbyl substituent” or “hydrocarbyl group” is found in paragraphs[0137] to [0141] of published application US 2010/0197536.

Another suitable hydrocarbyl substituted nitrogen containing additive isa succinimide dispersant, which may also be referred to as a succinimidefuel detergent. In one embodiment, the succinimide dispersant is acondensation product of hydrocarbyl-substituted succinic anhydride or areactive equivalent thereof (e.g., an anhydride, ester, or acid halide),with an amine such as a polyethylene polyamine. Succinimide dispersantsmay generally be viewed as comprising a variety of chemical structuresincluding typically

where each R¹ is independently an alkyl group, frequently apolyisobutylene group with a molecular weight (M_(n)) of 500-5000 basedon the polyisobutylene precursor, and R² are alkylene groups, commonlyethylene (C₂H₄) groups. Such molecules are commonly derived fromreaction of an alkenyl acylating agent with a polyamine, and a widevariety of linkages between the two moieties is possible beside thesimple imide structure shown above, including a variety of amides andquaternary ammonium salts. In the above structure, the amine portion isshown as an alkylene polyamine, although other aliphatic and aromaticmono- and polyamines may also be used, including those described aboveand below. Also, a variety of modes of linkage of the R¹ groups onto theimide structure are possible, including various cyclic linkages. Theratio of the carbonyl groups of the acylating agent to the nitrogenatoms of the amine may be 1:0.5 to 1:3, and in other instances 1:1 to1:2.75 or 1:1.5 to 1:2.5. Succinimide dispersants are more fullydescribed in U.S. Pat. Nos. 4,234,435 and 3,172,892 and in EP 0355895.

Succinimide dispersants may also be described as being prepared fromhydrocarbyl-substituted succinic acylating agent which are, in turn,prepared by the so-called “chlorine” route or by the so-called “thermal”or “direct alkylation” route. These routes are described in detail inpublished application US 2005-0202981, paragraphs 0014 through 0017. Adirect alkylation or low-chlorine route is also described in U.S. Pat.No. 6,077,909; refer to column 6 line 13 through col. 7 line 62 andcolumn 9 lines 10 through col. 10 line 11. Illustrative thermal ordirect alkylation processes involve heating a polyolefin, typically at180 to 250° C., with maleic anhydride under an inert atmosphere. Eitherreactant may be in excess. If the maleic anhydride is present in excess,the excess may be removed after reaction by distillation. Thesereactions may employ, as the polyolefin, high vinylidenepolyisobutylene, that is, having greater than 50, 70, or 75% terminalvinylidene groups, in some embodiments alpha vinylidene end groups. Incertain embodiments, the succinimide dispersant may be prepared by thedirect alkylation route. In other embodiments, it may comprise a mixtureof direct alkylation and chlorine-route dispersants.

Any of these additives may be post-treated with any of a variety ofagents to impart desirable properties thereto. Such post-treatmentincludes reaction with urea, thiourea, dimercaptothiadiazoles, carbondisulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substitutedsuccinic anhydrides, nitriles, epoxides, boron compounds such as boricacid, phosphorus compounds, or mixtures thereof. References detailingsuch treatment are listed in U.S. Pat. No. 4,654,403.

Additional suitable hydrocarbyl substituted nitrogen containingadditives include acylated amines, hydrocarbyl substituted amines, ormixtures thereof.

Suitable acylated amines include reaction products of one or morecarboxylic acylating agent and one or more amine. The carboxylicacylating agents include C₈₋₃₀ fatty acids, C₁₄₋₂₀ isoaliphatic acids,C₁₈₋₄₄ dimer acids, addition dicarboxylic acids, trimer acids, additiontricarboxylic acids, and hydrocarbyl substituted carboxylic acylatingagents, including those described above. Dimer acids are described inU.S. Pat. Nos. 2,482,760, 2,482,761, 2,731,481, 2,793,219, 2,964,545,2,978,468, 3,157,681, and 3,256,304. Suitable amines may be any of thosedescribed above, in some embodiments a polyamine, such as analkylenepolyamine or a condensed polyamine. Acylated amines, theirintermediates and methods for preparing the same are described in U.S.Pat. Nos. 3,219,666; 4,234,435; 4,952,328; 4,938,881; 4,957,649;4,904,401; and 5,053,152.

The hydrocarbyl substituted nitrogen containing additive may also be ahydrocarbyl-substituted amine. These hydrocarbyl-substituted amines arewell known to those skilled in the art. These amines are disclosed inU.S. Pat. Nos. 3,275,554; 3,438,757; 3,454,555; 3,565,804; 3,755,433;and 3,822,289. Typically, hydrocarbyl substituted amines are prepared byreacting olefins and olefin polymers, including the above polyalkenesand halogenated derivatives thereof, with amines (mono- or polyamines).The amines may be any of the amines described herein, and in someembodiments is an alkylenepolyamine.

Examples of hydrocarbyl substituted amines include ethylene polyaminessuch as diethylenetriamine; poly(propylene)amine;N,N-dimethyl-N-poly(ethylene/propylene)amine, (50:50 mole ratio ofmonomers); polybutene amine; N,N-di(hydroxyethyl)-N-polybutene amine;N-(2-hydroxypropyl)-N-polybutene amine; N-polybutene-aniline;N-polybutenemorpholine; N-poly(butene)ethylenediamine;N-poly(propylene)trimethylenediamine; N-poly(butene)diethylenetriamine;N′,N′-poly(butene)tetraethylenepentamine;N,N-dimethyl-N′-poly(propylene)-1,3-propylenediamine and the like.

In some embodiments, the hydrocarbyl substituted nitrogen containingadditives described above are borated. Any of the additives describedherein may be borated, generally prepared by the reaction of theadditive with a boron-containing compound, for example, boric acid.

In one embodiment, the boron compound is a borated dispersant.Typically, the borated dispersant contains from about 0.1% to about 5%,or from about 0.5% to about 4%, or from 0.7% to about 3% by weightboron. In one embodiment, the borated dispersant is a borated acylatedamine, such as a borated succinimide dispersant. Borated dispersants aredescribed in U.S. Pat. Nos. 3,000,916; 3,087,936; 3,254,025; 3,282,955;3,313,727; 3,491,025; 3,533,945; 3,666,662 and 4,925,983. In oneembodiment, the boron compound is an alkali or mixed alkali metal andalkaline earth metal borate. These metal borates are generally hydratedparticulate metal borates which are known in the art. Alkali metalborates include mixed alkali and alkaline metal borates. These metalborates are available commercially. Representative patents disclosingsuitable alkali and alkali metal and alkaline earth metal borates andtheir methods of manufacture include U.S. Pat. Nos. 3,997,454;3,819,521; 3,853,772; 3,907,601; 3,997,454; and 4,089,790.

Hydrocarbyl substituted nitrogen containing additives described abovecan also be post-treated by reaction with any of a variety of agentsbesides borating agents. Among these are urea, thiourea,dimercaptothiadiazoles, carbon disulfide, aldehydes, ketones, carboxylicacids, hydrocarbon-substituted succinic anhydrides, nitriles, epoxides,and phosphorus compounds. References detailing such treatment are listedin U.S. Pat. No. 4,654,403.

The amines used in the preparation of the hydrocarbyl substitutednitrogen containing additives described above may be polyamines.Suitable polyamines include aliphatic, cycloaliphatic, heterocyclic andaromatic polyamines. Examples of the polyamines include alkylenepolyamines, hydroxy containing polyamines, aryl polyamines, andheterocyclic polyamines.

Alkylene polyamines are represented by the formula:

(H)(R₅)N-(Alkylene-N)_(n)—(R₅)(R₅)

wherein n has an average value from 1, or about 2 to about 10, or toabout 7, or to about 5, and the “Alkylene” group has from 1, or about 2to about 10, or to about 6, or to about 4 carbon atoms. Each R₅ isindependently hydrogen, or an aliphatic or hydroxy-substituted aliphaticgroup of up to about 30 carbon atoms.

Such alkylenepolyamines include methylenepolyamines, ethylenepolyamines,butylenepolyamines, propylenepolyamines, pentylenepolyamines, etc. Thehigher homologs and related heterocyclic amines such as piperazines andN-aminoalkyl-substituted piperazines are also included. Specificexamples of such polyamines are ethylenediamine, diethylenetriamine(DETA), triethylenetetramine (TETA), tris-(2-aminoethyl)amine,propylenediamine, trimethylenediamine, tripropylenetetramine,tetraethylenepentamine, hexa-ethyleneheptamine, pentaethylenehexamine,etc.

Higher homologs obtained by condensing two or more of the above-notedalkylene amines are similarly useful as are mixtures of two or more ofthe aforedescribed polyamines.

Ethylenepolyamines, such as those mentioned above, are useful. Suchpolyamines are described in detail under the heading Ethylene Amines inKirk Othmer's “Encyclopedia of Chemical Technology”, 2d Edition, Vol. 7,pages 22-37, Interscience Publishers, New York (1965). Such polyaminesare most conveniently prepared by the reaction of ethylene dichloridewith ammonia or by reaction of an ethylene imine with a ring openingreagent such as water, ammonia, etc. These reactions result in theproduction of a complex mixture of polyalkylenepolyamines includingcyclic condensation products such as the aforedescribed piperazines.Ethylenepolyamine mixtures are also useful.

Other useful types of polyamine mixtures are those resulting fromstripping of the above-described polyamine mixtures to leave as residuewhat is often termed “polyamine bottoms”. In general, alkylenepolyaminebottoms can be characterized as having less than two, usually less than1% (by weight) material boiling below about 200° C. A typical sample ofsuch ethylene polyamine bottoms obtained from the Dow Chemical Companyof Freeport, Tex. designated “E-100” has a specific gravity at 15.6° C.of 1.0168, a percent nitrogen by weight of 33.15 and a viscosity at 40°C. of 121 centistokes. Gas chromatography analysis of such a samplecontains about 0.93% “Light Ends” (most probably DETA), 0.72% TETA,21.74% tetraethylene pentamine and 76.61% pentaethylenehexamine andhigher (by weight). These alkylenepolyamine bottoms include cycliccondensation products such as piperazine and higher analogs ofdiethylenetriamine, triethylenetetramine and the like. Thesealkylenepolyamine bottoms can be reacted solely with the acylating agentor they can be used with other amines, polyamines, or mixtures thereof.

Another useful polyamine is a condensation reaction between at least onehydroxy compound with at least one polyamine reactant containing atleast one primary or secondary amino group. The hydroxy compounds are insome embodiment's polyhydric alcohols and amines. The polyhydricalcohols are described above. In some embodiments, the hydroxy compoundsare polyhydric amines. Polyhydric amines include any of theabove-described monoamines reacted with an alkylene oxide (e.g.,ethylene oxide, propylene oxide, butylene oxide, etc.) having two toabout 20, or to about four carbon atoms. Examples of polyhydric aminesinclude tri-(hydroxypropyl)amine, tris-(hydroxymethyl)amino methane,2-amino-2-methyl-1,3-propanediol,N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylene diamine, andN,N,N′,N′-tetrakis(2-hydroxyethyl)ethylenediamine, and in someembodiments tris(hydroxymethyl)aminomethane (THAM).

In another embodiment, the polyamines are hydroxy-containing polyamines.Hydroxy-containing polyamine analogs of hydroxymonoamines, particularlyalkoxylated alkylenepolyamines (e.g., N,N(diethanol)ethylenediamine) mayalso be used. Such polyamines may be made by reacting theabove-described alkylenepolyamines with one or more of theabove-described alkylene oxides. Similar alkylene oxide-alkanolaminereaction products may also be used such as the products made by reactingthe aforedescribed primary, secondary or tertiary alkanolamines withethylene, propylene or higher epoxides in a 1:1 to 1:2 molar ratio.Reactant ratios and temperatures for carrying out such reactions areknown to those skilled in the art.

Specific examples of alkoxylated alkylene polyamines includeN-(2-hydroxyethyl)ethylenediamine,N,N-bis(2-hydroxyethyl)ethylenediamine, 1-(2-hydroxyethyl)piperazine,mono(hydroxypropyl)substituted tetraethylenepentamine,N-(3-hydroxybutyl)tetraethylene diamine, etc. Higher homologs obtainedby condensation of the above-illustrated hydroxy-containing polyaminesthrough amino groups or through hydroxy groups are likewise useful.Condensation through amino groups results in a higher amine accompaniedby removal of ammonia while condensation through the hydroxy groupsresults in products containing ether linkages accompanied by removal ofwater. Mixtures of two or more of any of the aforesaid polyamines arealso useful.

In another embodiment, the amine is a heterocyclic polyamine. Theheterocyclic polyamines include aziridines, azetidines, azolidines,pyridines, pyrroles, indoles, piperidines, imidazoles, piperazines,isoindoles, purines, morpholines, thiomorpholines,N-aminoalkylmorpholines, N-aminoalkylthiomorpholines,N-aminoalkylpiperazines, N,N′-di aminoalkylpiperazines, azepines,azocines, azonines, azecines and tetra-, di- and perhydro derivatives ofeach of the above and mixtures of two or more of these heterocyclicamines. In some embodiments, the heterocyclic amines are the saturated5- and 6-membered heterocyclic amines containing only nitrogen, oxygenand/or sulfur in the hetero ring, especially the piperidines,piperazines, thiomorpholines, morpholines, pyrrolidines, and the like.Piperidine, aminoalkyl-substituted piperidines, piperazine,aminoalkyl-substituted piperazines, morpholine, aminoalkyl-substitutedmorpholines, pyrrolidine, and aminoalkyl-substituted pyrrolidines.Usually the aminoalkyl substituents are substituted on a nitrogen atomforming part of the hetero ring. Specific examples of such heterocyclicamines include N-aminopropylmorpholine, N-amino-ethylpiperazine, andN,N′-diaminoethylpiperazine. Hydroxy heterocyclic polyamines are alsouseful. Examples include N-(2-hydroxyethyl)cyclohexylamine,3-hydroxycyclopentylamine, para-hydroxyaniline,N-hydroxyethylpiperazine, and the like.

The amines used in the preparation of the hydrocarbyl substitutednitrogen containing additives described above may also be amines havingat least 4 aromatic groups, at least one —NH₂ functional group, and atleast 2 secondary or tertiary amino groups.

Suitable amines having at least 3 aromatic groups, at least one —NH₂functional group, and at least 2 secondary or tertiary amino groups maybe represented by the formula:

wherein independently each variable may be defined as follows: R¹ may behydrogen or a C₁₋₅ alkyl group (typically hydrogen); R² may be hydrogenor a C₁₋₅ alkyl group (typically hydrogen); U may be an aliphatic,alicyclic or aromatic group, with the proviso that when U is aliphatic,the aliphatic group may be linear or branched alkylene group containing1 to 5, or 1 to 2 carbon atoms; and w may be 1 to 10, or 1 to 4, or 1 to2 (typically 1).

Suitable amines having at least 3 aromatic groups, at least one —NH₂functional group, and at least 2 secondary or tertiary amino groups maybe represented by the formula:

wherein independently each variable may be defined as follows: R¹ may behydrogen or a C₁₋₅ alkyl group (typically hydrogen); R² may be hydrogenor a C₁₋₅ alkyl group (typically hydrogen); U may be an aliphatic,alicyclic or aromatic group, with the proviso that when U is aliphatic,the aliphatic group may be linear or branched alkylene group containing1 to 5, or 1 to 2 carbon atoms; and w may be 1 to 10, or 1 to 4, or 1 to2 (typically 1).

Alternatively, the amines may also be represented by the formula:

wherein each variable U, R¹, and R² are the same as described above andw is 0 to 9 or 0 to 3 or 0 to 1 (typically 0).

Examples of suitable amines having at least 3 aromatic groups may berepresented by any of the following formulae:

In one embodiment, the amine having at least 3 aromatic groups mayinclude mixtures of compounds represented by the formulae disclosedabove. A person skilled in the art will appreciate that these compoundsmay also react with the aldehyde described below to form acridinederivatives. In addition to such compounds, a person skilled in the artwill also appreciate that other acridine structures may be possiblewhere the aldehyde reacts with other benzyl groups bridged with the >NHgroup. Any or all of the N-bridged aromatic rings are capable of suchfurther condensation and perhaps aromatization.

Examples of suitable amines having at least 3 aromatic groups may bebis[p-(p-aminoanilino)phenyl]-methane,2-(7-amino-acridin-2-ylmethyl)-N-4-{4-[4-(4-amino-phenylamino)-benzyl]-phenyl}-benzene-1,4-diamine,N⁴-{4-[4-(4-amino-phenylamino)-benzyl]-phenyl}-2-[4-(4-amino-phenylamino)-cyclohexa-1,5-dienylmethyl]-benzene-1,4-diamine,N-[4-(7-amino-acridin-2-ylmethyl)-phenyl]-benzene-1,4-diamine, ormixtures thereof.

In one embodiment, the amine having at least 3 aromatic groups may bebis[p-(p-aminoanilino)phenyl]-methane,2-(7-amino-acridin-2-ylmethyl)-N-4-{4-[4-(4-amino-phenylamino)-benzyl]-phenyl}-benzene-1,4-diamineor mixtures thereof.

The amine having at least 3 aromatic groups may be prepared by a processcomprising reacting an aldehyde with an amine (typically4-aminodiphenylamine). The resultant amine may be described as analkylene coupled amine having at least 3 aromatic groups, at least one—NH₂ functional group, and at least 2 secondary or tertiary aminogroups.

In some embodiments, the hydrocarbyl substituted nitrogen containingadditives are succinimide dispersants. In some embodiments, thehydrocarbyl substituted nitrogen containing additives are non-boratedsuccinimide dispersants. In some embodiments, the succinimidedispersants are derived from an alkyl aryl amine, polyethylenepolyamines, or some combination thereof. In some embodiments, thesuccinimide dispersants are derived from a hydrocarbyl-substitutedsuccinic anhydride or acid (a reactive equivalent thereof e.g., anester, acid halide, etc.) where the hydrocarbyl-substituted succinicanhydride contains a polyisobutylene group with a molecular weight from500 to 3000, or from 1600 to 3000, or from 1000 to 2000.

Suitable hydrocarbyl substituted nitrogen containing additives alsoinclude quaternary ammonium salts, also referred to as quaternaryammonium salt detergents and/or dispersants. Examples of suitablequaternary ammonium salts include (i) imide quaternary ammonium salts,(ii) Mannich quaternary ammonium salts, (iii) polyalkene substitutedamine quaternary ammonium salts, (iv) amide quaternary ammonium salts,(v) ester quaternary ammonium salts, (vi) polyester quaternary ammoniumsalts, or (vii) any combination thereof.

These various types of quaternary ammonium salts may be prepared in anynumber of ways but generally are prepared by reacting a non-quaternizednitrogen-containing compound with a quaternizing agent. Each of thedifferent types of quaternary ammonium salts described uses a differentnon-quaternized nitrogen-containing compound in its preparation, butgenerally the non-quaternized nitrogen-containing compound contains atertiary nitrogen capable of being quaternized (or a primary orsecondary nitrogen atom that can be alkylated to a tertiary nitrogenthat can then be quaternized) and a hydrocarbyl substituent group. Thenon-quaternized compounds are typically detergents and/or dispersantsthemselves, put once converted to quaternary ammonium salts, can provideimproved performance.

The hydrocarbyl substituent groups of the quaternary ammonium saltdetergents and/or dispersants, and/or of the non-quaternizednitrogen-containing compounds from which they are prepared, are notoverly limited and may be any of the hydrocarbyl substituent groupsderived herein.

Each of the quaternary ammonium salts described above is prepared usinga quaternizing agent. Suitable quaternizing agents are not overlylimited so long as they are able to convert the tertiary nitrogen of thenon-quaternized precursor to a quaternized nitrogen. Suitablequaternizing agents include dialkyl sulfates, benzyl halides,hydrocarbyl substituted carbonates, hydrocarbyl epoxides, esters ofcertain polycarboxylic acids, or mixtures thereof. Any of the theseagents, including the hydrocarbyl epoxides and hydrocarbyl substitutedcarbonates, may be used in combination with an acid, for example aceticacid. Suitable acids include carboxylic acids, such as acetic acid,propionic acid, 2-ethylhexanoic acid, and the like. In some embodiments,including, for example, the amide quaternary ammonium salts, thequaternizing agents, including the hydrocarbyl epoxides and hydrocarbylsubstituted carbonates, are used without the addition of such an acid.In some embodiments, particularly when no acid is used, some amount ofwater is present during the reaction.

In some embodiments, the quaternizing agent can be a hydrocarbylepoxides, as represented by the following formula:

wherein R¹⁵, R¹⁶, R¹⁷ and R¹⁸ can be independently H or a C₁₋₅₀hydrocarbyl group. Examples of suitable hydrocarbyl epoxides include:styrene oxide, ethylene oxide, propylene oxide, butylene oxide, stilbeneoxide, C₂₋₅₀ epoxides, or combinations thereof.

With regards to the amide quaternary ammonium salt described above, thepresence of the amide group and its impact on the rest of the structureallows the salt to be “self-salting” and thus not requiring of aseparate anion assuming the structure also includes at least one otheracid group. For example, when hydrocarbyl substituted succinicanhydrides, and similar materials are used to prepare thenon-quaternized nitrogen-containing compounds, the resulting quaternaryammonium salt can have an amide group and an acid group, where the acidgroup becomes the counter anion for the quaternized nitrogen or theresulting amide quaternary ammonium salt. These materials may bedescribed as betaines. The preparation of these quaternary ammoniumsalts is typically marked by the use of an alkylene oxide quaternizingagent, or a similar agent, without the addition of a separate acid.

In another embodiment, the quaternizing agent can be an ester of acarboxylic acid or an ester of a polycarboxylic acid. In someembodiments, the quaternizing agent includes dimethyl oxalate, methyl2-nitrobenzoate and methyl salicylate.

In some embodiments, the quaternary ammonium salt is a quaternizedpolymer formed by polymerizing the condensation product of ahydrocarbyl-substituted acylating agent and a compound having an oxygenor nitrogen atom capable of condensing the acylating agent wherein thecondensation product has at least one tertiary amino group, or evenpolymerizing the hydrocarbyl-substituted acylating agent which is thenreacted with a compound having an oxygen or nitrogen atom. One or moreof the tertiary amino groups on the polymer may then be quaternizedusing the methods described herein resulting in a quaternized polymer.

Any of the quaternary ammonium salts described above may be derived inthe presence of a protic solvent. In some embodiments, the process usedto prepare these additives is substantially free of to free of methanol.In one embodiment, the protic solvent includes compounds that contain 1or more hydroxyl functional groups, and may include water. In someembodiments, the protic solvent is water.

Additional details on quaternary ammonium salts, examples thereof andmethods of making the same can be found in U.S. Pat. Nos. 7,951,211 and7,906,470, US published applications US 2008/0113890, US 2012/0010112,and US 2011/0315107, and international publications WO 2010/132259, WO2010/097624, and WO 2011/095819.

The nitrogen containing dispersant may be a polyetheramine. In someembodiments, the polyetheramine can include compounds having two or moreconsecutive ether groups and at least one primary, secondary or tertiaryamine group where the amine nitrogen has some basicity. Thepolyetheramines of this invention can include poly(oxyalkylene) amineshaving a sufficient number of repeating oxyalkylene units to render thepoly(oxyalkylene)amine soluble in a normally liquid fuel, such as, inhydrocarbons boiling in a gasoline or diesel fuel range and blends ofhydrocarbon fuel with non-hydrocarbon fuel. Generally,poly(oxyalkylene)amines having at least 5 oxyalkylene units are suitablefor use in the present invention.

Poly(oxyalkylene)amines can include:hydrocarbylpoly(oxyalkylene)-amines,hydrocarbylpoly(oxyalkylene)polyamines, hydropoly(oxyalkylene)-amines,hydropoly(oxyalkylene)polyamines, and derivatives of polyhydric alcoholshaving at least two poly(oxyalkylene)amine and/or poly(oxyalkylene)polyamine chains on the molecule of the derivative.

In one embodiment, the poly(oxyalkylene)amine for use in the inventionis represented by the formula:

R⁶O(A²O)_(m)R⁷NR⁸R⁹

wherein R⁶ is a hydrocarbyl group of 1 to 50 carbon atoms, or 8 to 30carbon atoms; A² is an alkylene group having 2 to 18 carbon atoms and insome embodiments 2 to 6 carbon atoms; m is a number from 1 to 50; R⁷ isan alkylene group having 2 to 18 carbon atoms or in some embodiments 2to 6 carbon atoms; and R⁸ and R⁹ are independently hydrogen, ahydrocarbyl group or —[R′N(R″)]nR′″ wherein R′ is an alkylene grouphaving 2 to 6 carbon atoms, R″ and R′″ are independently hydrogen or ahydrocarbyl group, and n is a number from 1 to 7.

In another embodiment, the poly(oxyalkylene)amine of the presentinvention can be represented by the formula:

R¹⁰O[CH₂CH(CH₂CH₃)O]_(Z)CH₂CH₂CH₂NH₂

wherein R¹⁰ is an aliphatic group or alkyl-substituted phenyl group of 8to 30 carbon atoms; and Z is a number from 12 to 30. In yet anotherembodiment, the poly-(oxyalkylene)amine of the present invention can berepresented by the formula above wherein R¹⁰ isCH₃CH(CH₃)[CH₂CH(CH₃)]₂CH(CH₃)CH₂CH₂— and Z is a number from 16 to 28.Poly(oxyalkylene)amines of the present invention can have a molecularweight in the range from 300 to 5,000.

The polyetheramines of the present invention can be prepared by usingthe polyethers described above as intermediates and converting them topolyetheramines. The polyether intermediates can be converted topolyetheramines by several methods. The polyether intermediate can beconverted to a polyetheramine by a reductive amination with ammonia, aprimary amine or a polyamine as described in U.S. Pat. Nos. 5,112,364and 5,752,991. In one embodiment, the polyether intermediate can beconverted to a polyetheramine via an addition reaction of the polyetherto acrylonitrile to form a nitrile which is then hydrogenated to formthe polyetheramine. U.S. Pat. No. 5,264,006 provides reaction conditionsfor the cyanoethylation of the polyether with acrylonitrile and thesubsequent hydrogenation to form the polyetheramine. In yet anotherembodiment, the polyether intermediate or poly(oxyalkylene) alcohol isconverted to the corresponding poly(oxyalkylene) chloride via a suitablechlorinating agent followed by displacement of chlorine with ammonia, aprimary or secondary amine, or a polyamine as described in U.S. Pat. No.4,247,301.

The mixed alkoxylates of the present invention may also include analkoxylated fatty amine, which can include amines represented by theformula:

wherein R¹¹ is a hydrocarbyl group having 4 to 30 carbon atoms, A³ andA⁴ are vicinal alkylene groups, and the sum of x and y is an integerthat is at least 1. The hydrocarbyl group is a univalent radical ofcarbon atoms that is predominantly hydrocarbon in nature, but can havenonhydrocarbonaceous substituent groups and can have heteroatoms. Thehydrocarbyl group R¹¹ can be an alkyl or alkylene group of 4 to 30carbon atoms, or 10 to 22 carbon atoms. The vicinal alkylene groups A³and A⁴ can be the same or different and include: ethylene(—CH₂—),propylene (—CH₂CH₂CH₂—) and butylene (—CH₂CH₂CH₂CH₂—) having the carbonto nitrogen and carbon to oxygen bonds on adjacent or neighboring carbonatoms. Examples of alkoxylated fatty amines can include: diethoxylatedtallowamine, diethoxylated oleylamine, diethoxylated stearylamine, andthe diethoxylated amine from soybean oil fatty acids. Alkoxylated fattyamines are commercially available from Akzo under the Ethomeen® series.

The nitrogen-containing compound may be present at 0.01 percent byweight to 5 percent by weight, or 0.1 percent by weight to 3 percent byweight, or 0.2 percent by weight to 1.5 percent by weight, or 0.25percent by weight to 1 percent by weight, or 0.5 percent by weight to 1percent by weight of the described composition.

The Sulfur-Containing Compound

In some embodiments, the bearing lubricant of invention, or the methodsusing the same, may also include (d) a sulfur-containing compound.

Suitable sulfur-containing compounds include sulfurized olefins. Any theolefins described herein for other components are also suitable olefinsfrom which sulfurized olefins may be prepared. In some examples, thesulfur-containing compound is a sulfurized olefin derived fromisobutylene, butylene, propylene, ethylene, or some combination thereof.In some examples, the sulfur-containing compound is a sulfurized olefinderived any of the natural oils or synthetic oils described above, oreven some combination thereof. For example, the sulfurized olefin may bederived from vegetable oil.

When present, the sulfur-containing compound may be present at 0.01percent by weight to 5 percent by weight, or 0.1 percent by weight to 3percent by weight, or 0.2 percent by weight to 1.5 percent by weight, or0.25 percent by weight to 1 percent by weight, or 0.5 percent by weightto 1 percent by weight of the described composition.

Additional Additives

Optionally, the lubricating compositions of the invention include one ormore additional additives, which may be selected from the groupincluding: a foam inhibitor, a demulsifier, a pour point depressant, anantioxidant, a dispersant other than those described above, a metaldeactivator (such as a copper deactivator), an antiwear agent other thanthose described above, extreme pressure agent, viscosity modifiers, ormixtures thereof. The optional additives may each be present in therange from 50, 75, 100 or even 150 ppm up to 5, 4, 3, 2 or even 1.5percent by weight, or from 75 ppm to 0.5 percent by weight, from 100 ppmto 0.4 percent by weight, or from 150 ppm to 0.3 percent by weight,where the percent by weight values are with regards to the overalllubricating oil composition. However, it is noted that some optionaladditives, including viscosity modifying polymers, which mayalternatively be considered as part of the base fluid, may be present inhigher amounts including up to 30, 40, or even 50% by weight whenconsidered separate from the base fluid. The optional additives may beused alone or mixtures thereof.

Antifoams, also known as foam inhibitors, are known in the art andinclude but are not limited to organic silicones and non-silicon foaminhibitors. Examples of organic silicones include dimethyl silicone andpolysiloxanes. Examples of non-silicon foam inhibitors include but arenot limited to polyethers, polyacrylates and mixtures thereof as well ascopolymers of ethyl acrylate, 2-ethylhexylacrylate, and optionally vinylacetate. In some embodiments, the antifoam is a polyacrylate. Antifoamsmay be present in the composition from 0.001 to 0.012 or 0.004 pbw oreven 0.001 to 0.003.

Demulsifiers are known in the art and include but are not limited toderivatives of propylene oxide, ethylene oxide, polyoxyalkylenealcohols, alkyl amines, amino alcohols, diamines or polyamines reactedsequentially with ethylene oxide or substituted ethylene oxides ormixtures thereof. Examples of demulsifiers include polyethylene glycols,polyethylene oxides, polypropylene oxides, (ethylene oxide-propyleneoxide) polymers and mixtures thereof. In some embodiments, thedemulsifiers is a polyether. Demulsifiers may be present in thecomposition from 0.002 to 0.012 pbw.

Pour point depressants are known in the art and include but are notlimited to esters of maleic anhydride-styrene copolymers,polymethacrylates; polyacrylates; polyacrylamides; condensation productsof haloparaffin waxes and aromatic compounds; vinyl carboxylatepolymers; and terpolymers of dialkyl fumarates, vinyl esters of fattyacids, ethylene-vinyl acetate copolymers, alkyl phenol formaldehydecondensation resins, alkyl vinyl ethers and mixtures thereof.

The compositions of the invention may also include a rust inhibitor,other than some of the additive described above. Suitable rustinhibitors include hydrocarbyl amine salts of dialkyldithiophosphoricacid, hydrocarbyl amine salts of hydrocarbyl arenesulphonic acid, fattycarboxylic acids or esters thereof, an ester of a nitrogen-containingcarboxylic acid, an ammonium sulfonate, an imidazoline, mono-thiophosphate salts or esters, or any combination thereof; or mixturesthereof.

Examples of hydrocarbyl amine salts of dialkyldithiophosphoric acid ofthe invention include but are not limited to those described above, aswell as the reaction product(s) of diheptyl or dioctyl or dinonyldithiophosphoric acids with ethylenediamine, morpholine or Primene 81Ror mixtures thereof. Suitable hydrocarbyl amine salts of hydrocarbylarenesulphonic acids used in the rust inhibitor package of the inventionare represented by the formula:

wherein Cy is a benzene or naphthalene ring. R²⁸ is a hydrocarbyl groupwith about 4 to about 30, preferably about 6 to about 25, morepreferably about 8 to about 20 carbon atoms. z is independently 1, 2, 3,or 4 and most preferably z is 1 or 2. R²³, R²⁴ and R²⁵ are as describedabove.

Examples of hydrocarbyl amine salts of hydrocarbyl arenesulphonic acidof the invention include but are not limited to the ethylenediamine saltof dinonylnaphthalene sulfonic acid.

Examples of suitable fatty carboxylic acids or esters thereof includeglycerol monooleate and oleic acid. An example of a suitable ester of anitrogen-containing carboxylic acid includes oleyl sarcosine.

The rust inhibitors may be present in the range from 0.02-0.2, from 0.03to 0.15, from 0.04 to 0.12, or from 0.05 to 0.1 pbw of the lubricatingoil composition. The rust inhibitors of the invention may be used aloneor in mixtures thereof.

The lubricating compositions of the invention may also include a metaldeactivator. Metal deactivators are used to neutralise the catalyticeffect of metal for promoting oxidation in lubricating oil. Suitablemetal deactivators include but are not limited to triazoles,tolyltriazoles, a thiadiazole, or combinations thereof, as well asderivatives thereof. Examples include derivatives of benzotriazolesother than those described above, benzimidazole,2-alkyldithiobenzimidazoles, 2-alkyldithiobenzothiazoles,2-(N,N′-dialkyldithio-carbamoyl)benzothiazoles,2,5-bis(alkyl-dithio)-1,3,4-thiadiazoles,2,5-bis(N,N′-dialkyldithiocarbamoyl)-1,3,4-thiadiazoles,2-alkyldithio-5-mercapto thiadiazoles or mixtures thereof. Theseadditives may be used from 0.01 to 0.25 percent by weight in the overallcomposition.

In some embodiments, the metal deactivator is a hydrocarbyl substitutedbenzotriazole compound. The benzotriazole compounds with hydrocarbylsubstitutions include at least one of the following ring positions 1- or2- or 4- or 5- or 6- or 7-benzotriazoles. The hydrocarbyl groups containabout 1 to about 30, preferably about 1 to about 15, more preferablyabout 1 to about 7 carbon atoms, and most preferably the metaldeactivator is 5-methylbenzotriazole used alone or mixtures thereof.

The metal deactivators may be present in the range from 0.001 to 0.1,from 0.01 to 0.04 or from 0.015 to 0.03 pbw of the lubricating oilcomposition. Metal deactivators may also be present in the compositionfrom 0.002 or 0.004 to 0.02 pbw. The metal deactivator may be used aloneor mixtures thereof.

Antioxidants may also be present including (i) an alkylateddiphenylamine, and (ii) a substituted hydrocarbyl mono-sulfide. In someembodiments, the alkylated diphenylamines of the invention arebis-nonylated diphenylamine and bis-octylated diphenylamine. In someembodiments, the substituted hydrocarbyl monosulfides includen-dodecyl-2-hydroxyethyl sulfide, 1-(tert-dodecylthio)-2-propanol, orcombinations thereof. In some embodiments, the substituted hydrocarbylmonosulfide is 1-(tert-dodecylthio)-2-propanol.

The antioxidant package may also include sterically hindered phenols.Examples of suitable hydrocarbyl groups include but are not limited to2-ethylhexyl or n-butyl ester, dodecyl or mixtures thereof. Examples ofmethylene-bridged sterically hindered phenols include but are notlimited to 4,4′-methylene-bis(6-tert-butyl o-cresol),4,4′-methylene-bis(2-tert-amyl-o-cresol),2,2′-methylene-bis(4-methyl-6-tert-butylphenol),4,4′-methylene-bis(2,6-di-tertbutylphenol) or mixtures thereof.

In some embodiments, the compositions of the invention are essentiallyfree of, or even completely free of alkylated phenols, alkaryl amines,or both, or contain them at not more than 2.0 percent by weight, 1.0percent by weight, or even 0.5 percent by weight where the percent byweight values refer to the total amount of alkylated phenols and/oralkaryl amines present in the overall lubricant.

EXAMPLES

The invention will be further illustrated by the following examples,which set forth particularly advantageous embodiments. While theexamples are provided to illustrate the invention, they are not intendedto limit it.

Example Set 1

A set of examples of coal pulverizer lubricant compositions is prepared.The formulations of the examples are summarized in the table below inpercent by weight, with the phosphorus-containing compound and nitrogencontaining dispersant listed on an actives basis:

TABLE 1 Ex 1 Ex 2 Ex 3 Ex 9⁵ COMP COMP COMP Ex 4 Ex 5 Ex 6 Ex 7 Ex 8COMP Base 99.26 97.80 98.6 95.55 96.87 96.45 97.81 96.66 NA Medium¹Phosphorus- 0 1.47 0 1.87 1.93 0.95 0.97 1.43 NA containing compound²Nitrogen 0 0 1.21 1.87 0.48 1.89 0.49 1.19 NA Containing Dispersant³Additional 0.74 0.73 0.73 0.70 0.72 0.71 0.73 0.72 NA Additives⁴ ¹Thebase medium is a mixture of polyalphaolefin (Group IV) base oil andpolyisobutylene base oil. The same base medium is used in each exampleunless otherwise noted, and on a PBW basis is present in the same amountin each example. Differences in the percent by weight listed for eachexample is solely due the different amounts of the phosphorus-containingcompound and nitrogen containing dispersant that are in each example.²The phosphorus-containing compound in the examples is an alkenylphosphite. ³The nitrogen containing dispersant in the examples is asuccinimide dispersant. ⁴The same additional additive package is usedfor each example, and on a PBW basis is present in the same amount ineach example. Differences in the percent by weight listed for eachexample is solely due the different amounts of the phosphorus-containingcompound and nitrogen containing dispersant that are in each example.⁵Example 9 is a commercially available lubricant marketed for thisapplication. The formulation of the lubricant is not known and so thematerial is included only as an example of the conventional lubricantscommercially available for this application.

Each of the example lubricants is tested in a procedure that simulatesthe harsh conditions seen in the bearings of pulverizers, andspecifically coal pulverizers. Coal dust is added to the examplelubricant to simulate the contamination that occurs in the field and theimpact on lubricant performance is measured to demonstrate the examplesability to provide acceptable performance under those conditions. Thetest uses a high load KRL type tester and a SNR 32008.C test bearing.The test procedure involves the following steps:

-   -   (1) Clean a new test bearing in an ultrasonic bath with toluene        for 15 minutes. Rinse with textile spirits and allow the bearing        to dry.    -   (2) Obtain the start of test bearing weight to the tenth of a        milligram.    -   (3) Place bearing in the test head of the KRL type tester.    -   (4) Add 0.9 percent by weight coal dust to the example        lubricant. Mix the lubricant and coal dust well using a high        speed shaker and then fill the test head with 30 ml of the coal        dust contaminated example lubricant.    -   (5) Install test head into the KRL type tester.    -   (6) Run the test conditions outlined in Table 2, which are        designed to simulate the harsh conditions and manner of        operation experienced in the bearings of pulverizers:

TABLE 2 Speed Load Temp Time Phase (rpm) (kg) (Degrees C.) (hrs) BreakIn 150 800 90 1 Break In 300 800 90 1 Break In 430 800 90 2 Break In 1501600 90 1 Break In 300 1600 90 1 Break In 430 1600 90 2 Break In 1502400 90 1 Break In 300 2400 90 1 Test 430 2400 90 48

-   -   (7) At the end of test remove, save, and label the example        lubricant.    -   (8) Clean the test bearing by rinsing with textile spirits and        then clean the bearing in ultrasonic bath with toluene for 15        minutes. Rinse again with textile spirits and allow the bearing        to dry.    -   (9) Obtain the end of test bearing weight to the tenth of a        milligram.    -   (10) Determine weight loss from the start and end of test        weights and analyze the end of test example lubricant for the        amount of wear metals.

The results from the testing of the example lubricants are summarized inthe table below:

TABLE 3 Ex 1 Ex 2 Ex 3 Ex 9⁴ COMP COMP COMP Ex 4 Ex 5 Ex 6 Ex 7² Ex 8³COMP Total Weight 8.7 15.6 9.9 8.9 4.9 9.5 8.2 14.1 22.6 Loss (mg)¹ Ironin 172 266 229 322 337 293 128 294 770 Lubricant (ppm) ¹For the totalweight loss, the lower the value the better the performance of thelubricant. Total weight loss is the more important result presentedabove in regards to evaluating lubricant performance. ²The results shownfor Example 7 are the average of two test results. ³The results shownfor Example 8 are the average of three test results. ⁴The results shownfor Example 9 are the average of four test results.

The results show that the pulverizer bearing lubricants of the presentinvention, and the methods of using the same, can provide significantperformance under the harsh conditions seen by pulverizer bearings. Thedescribed lubricants and methods are particularly advantageous comparedto the current commercially available options for these applications.

Example Set 2

A second set of examples of coal pulverizer lubricant compositions isprepared without adding any additional additives. The formulations ofthe examples are summarized in the table below in percent by weight,with the phosphorus-containing compound and nitrogen containingdispersant listed on an actives basis:

TABLE 4 Ex 10⁵ Ex 12 Ex 16 Ex 17 COMP Ex 11⁵ COMP Ex 13 Ex 14 Ex 15 COMPCOMP Ex 18 Base NA NA 100 99.26 94.44 98.53 99.01 99.50 99.63 Medium¹Phosphorus- NA 0.50 0.00 0.50 3.70 0.98 0.99 0.00 0.25 containingcompound² Nitrogen NA 0.25 0.00 0.25 1.85 0.49 0.00 0.50 0.12 ContainingDispersant³ Additional NA 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00Additives⁴ ¹The base medium is a mixture of polyalphaolefin (Group IV)and polyisobutylene base oil. The same base medium is used in eachexample unless otherwise noted. See footnote 1 in Table 1 above. ²Thephosphorus-containing compound in the examples is an alkenyl phosphite.³The nitrogen containing dispersant in the examples is a succinimidedispersant. ⁴No additional additives are added to these examples.⁵Example 10 is a commercially available lubricant marketed for thisapplication. The formulation of the lubricant is not known and so thematerial is included only as an example of the conventional lubricantscommercially available for this application. Example 11 is the samecommercially available lubricant but now top treated with the additivecombination of the present invention.

The examples of Table 4 are evaluated in the same test proceduredescribed above. The results are summarized in the table below:

TABLE 5 Ex 10² Ex 12³ Ex 16 Ex 17 COMP Ex 11 COMP Ex 13 Ex 14 Ex 15 COMPCOMP Ex 18 Total Weight 22.6 21.5 8.7 8.7 11.4 11.3 4.7 13.3 4.2 Loss(mg)¹ Iron in 770 177 172 124 258 156 449 222 123 Lubricant (ppm) ¹Forthe total weight loss, the lower the value the better the performance ofthe lubricant. Total weight loss is the more important result presentedabove in regards to evaluating lubricant performance. ²The results shownfor Example 10 are the average of three test results. ³The results shownfor Example 11 are the average of four test results.

The results show that the pulverizer bearing lubricants of the presentinvention, and the methods of using the same, can provide significantperformance under the harsh conditions seen by pulverizer bearings. Thedescribed lubricants and methods are particularly advantageous comparedto the current commercially available options for these applications.

In particular, it is noted that the inventive examples (Examples 13, 14,15, and 18) all have better weight loss results than the conventionaland un-additized lubricants (Examples 10 and 12). Example 16 has a goodweight loss result but the amount of iron in the lubricant at end oftest is far too high. Likewise, Example 17 has a reasonable, but stillhigh, amount of iron, but has high weight loss. In contrast, theinventive examples give a good balance of results in both areas.Furthermore, the top treated commerical example (Example 12) showedsignificant improvement as well, when the present invention was appliedto it.

Each of the documents referred to above is incorporated herein byreference. Except in the Examples, or where otherwise indicated, allnumerical quantities in this description specifying amounts, reactionconditions, molecular weights, number of carbon atoms, etc., are to beunderstood as modified by the word “about.” Unless otherwise indicated,all percent and formulation values are on a weight basis. Unlessotherwise indicated, all molecular weights are number average molecularweights. Unless otherwise indicated, each chemical or compositionreferred to herein should be interpreted as being a commercial gradematerial which may contain the isomers, by-products, derivatives, andother such materials which are normally understood to be present in thecommercial grade. However, the amount of each chemical component ispresented exclusive of any solvent or diluent, which may be customarilypresent in the commercial material, unless otherwise indicated. It is tobe understood that the upper and lower amount, range, and ratio limitsset forth herein may be independently combined. Similarly, the rangesand amounts for each element of the invention can be used together withranges or amounts for any of the other elements. As used herein, theexpression “consisting essentially of” permits the inclusion ofsubstances that do not materially affect the basic and novelcharacteristics of the composition under consideration.

What is claimed is:
 1. A method of lubricating the bearings of a solidfuel pulverizer comprising the steps of: I. supplying to said bearings alubricant composition comprising: (a) an oil of lubricating viscosity;(b) a phosphorus-containing compound; and (c) a nitrogen-containingdispersant; and wherein the lubricant composition optionally furthercomprises: (d) a sulfur-containing compound.
 2. The method of claim 1wherein the oil of lubricating viscosity comprises a mineral base oil.3. The method of claim 2 wherein the oil of lubricating viscositycomprises a synthetic base oil.
 4. The method of claim 1 wherein thephosphorus-containing compound comprises an alkyl phosphite, aphosphoric acid ester, an amine salt of a phosphoric acid ester, or somecombination thereof.
 5. The method of claim 1 wherein thenitrogen-containing dispersant comprises: a polyetheramine; a boratedsuccinimide dispersant; a non-borated succinimide dispersant; a Mannichdispersant comprising the reaction product of a dialkylamine, analdehyde and a hydrocarbyl substituted phenol; or any combinationthereof.
 6. The method of claim 5 wherein the nitrogen-containingdispersant comprises a non-borated succinimide dispersant derived froman aromatic amine.
 7. The method of claim 1 wherein the lubricantcomposition further comprises: (d) a sulfur-containing compound.
 8. Themethod of claim 1 wherein the phosphorus-containing compound comprisesan alkyl phosphite and the nitrogen-containing dispersant comprises anon-borated succinimide dispersant.
 9. The method of claim 1 wherein thephosphorus-containing compound is present in the lubricant compositionfrom 0.01 to 5.0 percent by weight; and wherein the nitrogen-containingdispersant is present in the lubricant composition from 0.01 to 4.0percent by weight.
 10. A bearing lubricant for a solid fuel pulverizercomprising: (a) an oil of lubricating viscosity; (b) aphosphorus-containing compound; and (c) a nitrogen-containingdispersant.
 11. The bearing lubricant of claim 10 wherein thephosphorus-containing compound comprises an alkyl phosphite, aphosphoric acid ester, an amine salt of a phosphoric acid ester, or somecombination thereof.
 12. The bearing lubricant of claim 10 wherein thenitrogen-containing dispersant comprises: a polyetheramine; a boratedsuccinimide dispersant; a non-borated succinimide dispersant; a Mannichdispersant comprising the reaction product of a dialkylamine, analdehyde and a hydrocarbyl substituted phenol; or any combinationthereof.
 13. The bearing lubricant of claim 10 wherein thephosphorus-containing compound is present in the lubricant compositionfrom 0.01 to 5.0 percent by weight; and wherein the nitrogen-containingdispersant is present in the lubricant composition from 0.01 to 4.0percent by weight.
 14. The bearing lubricant of claim 10 wherein thebearing lubricant further comprises: (d) a sulfur-containing compound.15. The use of a lubricant composition to improve the service life ordurability of bearings in solid fuel pulverizing equipment, saidlubricant composition comprising: (a) an oil of lubricating viscosity;(b) a phosphorus-containing compound; and (c) a nitrogen-containingdispersant.